Insulating materials, such as silicon and silicon compounds, quartz, diamond, glass, ceramic or other materials are increasingly used for making micromechanical timepiece parts. As seen in FIGS. 2 and 3, it has been observed, in particular with a balance spring 7, that after a shock, coils tend to adhere to bar 2 which is detrimental to the isochronism of the oscillator.
This phenomenon may be aggravated by the contamination of bar 2 and/or balance spring 7 with impurities or lubricant during manufacture or wear, particularly in the event of shocks. It is thus clear that some of the coils of balance spring 7 may adhere to the bar because of impurities or lubricant even though the balance spring is electrically conductive.